From U.S. Pat. No. 3,351,363, a telescoping assembly is provided between an outer pipe and an inner pipe of the suction conduit for a telescoping vacuum-cleaner conduit system in which the inner pipe is provided with a row or strip of indexing recesses with which a detent body or locking member on the outer pipe cooperates. In this system, a guide sleeve is provided on the outer pipe and carries the detent member while an actuating sleeve is usually displaceable on the guide sleeve and defines a space into which the detent member can move so that in one position of the actuating sleeve on the guide sleeve, the detent member is locked in one of the recesses while in another position of the actuating sleeve, the detent member can pass out of a recess of the inner pipe and allow relative axial movement of the two pipes.
The patent provides inner and outer annular plastic bodies which cooperate during the actuation and between which compression and springs are provided. The principal drawback of this arrangement is that the mounting of the assembly is problematical.